Antibiotics, such as tetracyclines, are used as growth promoters and feed efficiency promoters in animals such as poultry and livestock, and for therapeutic and prophylactic disease control in animals such as poultry and livestock, fish, domesticated pets, and so forth. Such antibiotics are typically formulated in an animal feed premix or animal feed supplement containing the antibiotic and an edible carrier or diluent. These premixes or animal feed supplements may then be mixed with a sufficient quantity of an appropriate animal feed (e.g., livestock, poultry, fish, pet and/or other animal feed) to provide a final animal feed formulation having the desired level of active compound in the feed.
Prior art chlortetracycline-containing animal feed supplements prepared through normal fermentation and dehydration of the mycelium meal provide, at maximum, chlortetracycline potencies of about 26% to 28% by weight. The highest concentration currently available in a standardized feed supplement is 22%. (Since chlortetracycline hydrochloride is the reference standard for chlortetracycline feed grade materials, all chlortetracycline concentrations and percentages stated herein, unless indicated otherwise, are calculated as the hydrochloride equivalent, regardless of the form present (e.g., the free base, complexes or salts other than the hydrochloride, etc.)). In order to obtain higher chlortetracycline concentrations, it is possible add pure crystalline chlortetracycline hydrochloride USP to the mycelium meal to raise the potency. This, however, is not economical. Furthermore, because chlortetracycline hydrochloride is water soluble, there is a question of stability in finished feeds containing moistures of 10% or higher.
It would therefore be desirable to provide a chlortetracycline-containing animal feed premix or animal feed supplement suitable for use in the veterinary, animal nutrition, and animal husbandry arts that can be prepared directly from a fermentation product and that can be prepared in a high concentration without requiring the addition of the antibiotic in pure form and that has improved stability over chlortetracycline hydrochloride feed supplements.